Blenheim operating limits and checklists

[335th_GRAthos]

Originally Posted by Sammi79

Engine temps are behind your right shoulder above the fuel cocks.

Nicely hidden! thanks!

[Buzpilot]

Does Blenheim have the one-stage compressor modelled at all?
Seems impossible now to climb above 5-6k feet now.

Compared to Accu-sims P-47, the Cod engines are not any near realistic at temperatures.
Can even make a runway takeoff (no taxiing), without using cowlings.

[Blackdog_kt]

Actually, taking off with the cowl flaps closed is recommended in the pilot's notes for the Blenheim Mk.IV, they are supposed to be effective enough in terms of airflow getting through the engine once you start moving.

I'm sorry for pushing this back guys (i've been spending some time on other real life stuff lately and other aspects of the sim), i will try to finalize my copying of the relevant manual pieces and post it here sometime within the next couple of weeks

[Buzpilot]

AFAIK the Engine head temperatures (asuming engine temps are sylinder head temps), arent they also depending on fuel mix, and not just airflow/rpm?
Is it modelled in this game/sim?
Shouldn't setting correct mix, also increase rpm slightly, like in RoF?

[JG53Frankyboy]

AFAIK it has only auto rich and auto lean mixture setting...

[Buzpilot]

Originally Posted by JG53Frankyboy

AFAIK it has only auto rich and auto lean mixture setting...

The P-47 has, not sure the Blenheim has, was just using the P-47 as reference, because it too has a aircooled radial engine.

[phoenix1963]

In general the two crucial things are to keep below 4lbs boost on takeoff and switch to coarse pitch ASAP.

[EDIT] I should have read Redroach's exellent post on the page above before sounding off. I'l have to try the inner tanks when back from hols.

I've been up to 11k ft climbing on 3lbs boost but there's no second stage to any supercharger and the mix seems bad, just like the hurri used to be.

Frankly it needs work.

56RAF_phoenix

[Blackdog_kt]

Originally Posted by JG53Frankyboy

AFAIK it has only auto rich and auto lean mixture setting...

Correct. In the Blenheim the levers move all the way (like a gradual, fully manual mix system) but they only have two functions: anything forward of the middle of the lever's movement range is auto lean and anything from the middle and back is auto rich.

This is not a glitch with CoD, the Mk.IV pilot's operating handbook describes how the real aircraft uses such a system.

[phoenix1963]

Well, I've just about tried every combination of mixture, carb heating, pitch, gills (radiator flaps), throttle... and I always get engine failures as I climb out.

I eventually discovered that the lean/rich setting seems to be exactly as labelled next to the lever, fully back seems to be auto rich.

I warm the engine with gills open (as per Klem's excellent pdf posted above), but takeoff with them open, or temps get too high (contrary to Klem's info). I use the 100 octane outer tanks (contrary to Klem's info).

I allow the engine oil temp to get above 40C before revving a little.

I cycle the prop pitch before taking off to circulate oil.

When I take off, I DON'T engage boost override and limit to about 4 lbs boost - that seems to get rid of most of the failures on takeoff - keeping revs below about 2500 and VERY gently increasing throttle.

As soon as I'm wheels-up I reduce throttle to about 0 boost and it seems to run sweetly on about 2200 rpm.

So I get off the ground OK with this recipe, but then I always get gasket failures, governor failures etc at around 2000ft - this is despite closing gills to keep temps up and adding some carb heat.

What am I doing wrong?!

56RAF_phoenix